package com.tys.algorithm.bak.code2;

import java.util.Stack;

//获得栈中最小值
public class Code15_GetMinStack {
    //方法1：最小栈和数据栈不同步增长
    public static class MyStack1 {
        //定义数据栈和最小栈
        private Stack<Integer> stackData;
        private Stack<Integer> stackMin;

        public MyStack1() {
            this.stackData = new Stack<Integer>();
            this.stackMin = new Stack<Integer>();
        }

        //入栈
        public void push(int newNum) {
            if (this.stackMin.isEmpty()) {
                this.stackMin.push(newNum);
            } else if (newNum <= this.getmin()) {
                this.stackMin.push(newNum);
            }
            this.stackData.push(newNum);
        }

        //出栈
        public int pop() {
            if (this.stackData.isEmpty()) {
                throw new RuntimeException("Your stack is empty.");
            }
            int value = this.stackData.pop();
            if (value == this.getmin()) {
                this.stackMin.pop();
            }
            return value;
        }


        //获取最小栈顶值
        public int getmin() {
            if (this.stackMin.isEmpty()) {
                throw new RuntimeException("Your stack is empty.");
            }
            return this.stackMin.peek();
        }
    }

    //方法2：最小栈和数据栈，同步增长
    public static class MyStack2 {
        //定义数据栈和最小栈
        private Stack<Integer> stackData;
        private Stack<Integer> stackMin;

        public MyStack2() {
            this.stackData = new Stack<Integer>();
            this.stackMin = new Stack<Integer>();
        }

        //入栈
        public void push(int newNum) {
            if (this.stackMin.isEmpty()) {
                this.stackMin.push(newNum);
            } else if (newNum < this.getmin()) {
                this.stackMin.push(newNum);
            } else {
                int newMin = this.stackMin.peek();
                this.stackMin.push(newMin);
            }
            this.stackData.push(newNum);
        }

        //出栈
        public int pop() {
            if (this.stackData.isEmpty()) {
                throw new RuntimeException("Your stack is empty.");
            }
            this.stackMin.pop();
            return this.stackData.pop();
        }

        //获取最小栈栈顶值
        public int getmin() {
            if (this.stackMin.isEmpty()) {
                throw new RuntimeException("Your stack is empty.");
            }
            return this.stackMin.peek();
        }
    }

    public static void main(String[] args) {
        MyStack1 stack1 = new MyStack1();
        stack1.push(3);
        System.out.println("3==" + stack1.getmin());
        stack1.push(4);
        System.out.println("3==" + stack1.getmin());
        stack1.push(1);
        System.out.println("1==" + stack1.getmin());
        System.out.println("1==" + stack1.pop());
        System.out.println("3==" + stack1.getmin());
        System.out.println("================");

        MyStack2 stack2 = new MyStack2();
        stack2.push(3);
        System.out.println("3==" + stack2.getmin());
        stack2.push(4);
        System.out.println("3==" + stack2.getmin());
        stack2.push(1);
        System.out.println("1==" + stack2.getmin());
        System.out.println("1==" + stack2.pop());
        System.out.println("3==" + stack2.getmin());

    }

}
